ABO blood groups in humans are controlled by the gene I. It has three alleles – I^A I^B and i. Since there are three different alleles, six different genotypes are possible. How many phenotypes can occur?

1. Three

2. One

3. Four

4. Two

Select the correct statement from the ones given below with respect to dihybrid cross:

Sickle cell anaemia is:

Point mutation involves:

1. insertion

2. change in single base pair

3. duplication 

4. deletion

Study the pedigree chart given below:

What does it show?

Inheritance of skin colour in humans is an example of:

1. chromosomal aberration

2. point mutation

3. polygenic inheritance

4. codominance

Two genes R and Y are located very close on the chromosomal linkage map of the maize plant. When RRYY and rryy genotypes are hybridized, then F₂ segregation will show:

1. higher number of the recombinant types

2. segregation in the expected 9:3:3:1 ratio

3. segregation in a 3:1 ratio

4. higher number of the parental types

A common test to find the genotype of a hybrid is by:

1. crossing of one F₂ progeny with a male parent

2. crossing of one F₂ progeny with a female parent

3. studying the sexual behaviour of F₁ progenies

4. crossing of one F₁ progeny with a male parent

In pea plants, yellow seeds are dominant to green. If a heterozygous yellow-seeded plant is crossed with a green-seeded plant, what ratio of yellow and green-seeded plants would you expect in F1generation?

1. 50:50

2. 9:1

3. 1:3

4. 3:1